In microfluidics, reagents have to be pre-stored for later use for a relatively long period of time. These reagents are generally pre-stored in chambers prepared specifically therefor, with inlets and outlets of the chambers having to be sealed in a fluid-tight manner. U.S. Pat. No. 7,980,272 B2 discloses, for example, a microfluidic apparatus having a sample chamber, wherein the opening into the chamber is closed with a material removable by heating.